Polymerization of macrocyclic polyester oligomers at elevated temperature using rare earth element catalysts

ABSTRACT

Compounds containing a lanthanide rare earth element or yttrium are effective catalysts for the polymerization of macrocyclic polyester oligomers. The catalysts are stable at elevated temperatures, and the polymerization is rapid, resulting in high monomer conversion, high molecular weight, and a mechanically sound material.

This application claims the benefit of U.S. provisional Application No.60/626,264, filed Nov. 9, 2004, which is incorporated in its entirety asa part hereof for all purposes.

TECHNICAL FIELD

This invention relates to the polymerization of macrocyclic polyesteroligomer compositions. More particularly, it relates to a genus ofcatalysts for such polymerizations that provide rapid polymerizationwith high monomer conversion, producing high molecular weight,mechanically sound polymer.

BACKGROUND

Linear thermoplastic polyesters such as poly(alkylene terephthalate) aregenerally known and commercially available where the alkylene typicallyhas 2 to 8 carbon atoms. Linear polyesters have many valuablecharacteristics including strength, toughness, high gloss and solventresistance. Linear polyesters are conventionally prepared by thereaction of a diol with a dicarboxylic acid or its functionalderivative, typically a diacid halide or diester. Linear polyesters maybe fabricated into articles of manufacture by a number of knowntechniques including extrusion, compression molding, and injectionmolding.

Recently, macrocyclic polyester oligomers have been developed which haveunique properties that make them attractive as matrices for engineeringthermoplastic composites. The desirable properties stem from the factthat macrocyclic polyester oligomers exhibit low melt viscosity,allowing them easily to impregnate a dense fibrous preform followed bypolymerization to polyesters. Furthermore, certain macrocyclic polyesteroligomers melt and polymerize at temperatures well below the meltingpoint of the resulting polymer. Upon melting and in the presence of anappropriate catalyst, polymerization and crystallization can occurvirtually isothermally.

The preparation of macrocyclic poly(alkylene dicarboxylate) oligomersand their polymerization to linear polyesters is described in U.S. Pat.Nos. 5,039,783, 5,214,158, 5,231,161, 5,321,117 and 5,466,744; and isreviewed by D. J. Brunelle in Cyclic Polymers, Second Edition, [J. A.Semlyn (ed.), (2000), Kluwer Academic Publishers (Netherlands), pp.185-228]. The catalysts employed for such polymerization include variousorganotin compounds and titanate esters, usually in solutionpolymerization processes. Polymerization using these catalysts isparticularly successful in the case of poly(1,4-butylene terephthalate)(“PBT”) because of the low temperatures at which the polymerization canbe carried out. However, catalyst performance is limited by sensitivityto impurities present in the macrocyclic polyester oligomers,particularly acidic impurities. Such catalysts also lack adequatethermal stability at the high temperatures required for some polyesterpolymerizations. This is particularly the case of poly(1,3-propyleneterephthalate) (“PPT”).

Kamau et al. (Polymers for Advanced Technologies, 2003, Vol. 14, pp.492-501) used di-n-butyltin oxide to catalyze the ring openingpolymerization of a mixture of cyclic PPT oligomers at 300° C. undernitrogen for two hours. The linear polymer so produced had a viscosityaverage molecular weight of only 22,500. Use of a specially purified PPTdimer increased the viscosity average molecular weight only to 30,300.The long time required and low molecular weight, brittle materialsproduced indicate this is not a commercially viable process.

Lanthanide catalysts have been used in the synthesis of poly(ethyleneterephthalate) (“PET”) from dimethyl terephthalate and ethylene glycol(V. Ignatov et al., J. Appl. Poly. Sci., 1995, Vol. 58, pp. 771-777).While the lanthanide compounds were more efficient catalysts thantetrabutyltitanate and calcium acetylacetonate in the first stage of theprocess (transesterification), they were less active in the second stage(polycondensation). The first stage lasted typically about eightyminutes (mostly at 195° C.), and the second about 1.5-2.0 hours at268-270° C. The intrinsic viscosity of the lanthanide-catalyzed samplesranged from 0.65 to 0.82, compared with 0.85 with calciumacetylacetonate and 0.90 with tetrabutyltitanate.

U.S. Pat. No. 5,191,013 teaches the use of basic reagents, tinalkoxides, organotin compounds (i.e., compounds containing a Sn—C bond),titanate esters, and metal acetylacetonates as macrocyclic polyesteroligomer polymerization catalysts. The metal acetylacetonates areillustrated by Co(III) acetylacetonate and Fe(III) acetylacetonate,particularly in combination with an aliphatic alcohol, especially a diolsuch as 1,12-dodecanediol. The thermal stability of suchacetylacetonates is adequate for the ring opening polymerization ofmacrocyclic oligomers of poly(1,4-butylene terephthalate) (“PBT”), whichis conducted in the range of about 175-220° C. However, they lackthermal stability at the high temperatures (see, e.g., J. Von Hoene etal., J. Phys. Chem., 1958, Vol. 62, pp. 1098-1101 and R. G. Charles etal., J. Phys. Chem., 1958, Vol. 62, pp. 440-4) required for efficientpolymerizations of macrocyclic oligomers of, for example, PPT.

There thus remains a need for an effective and efficienthigh-temperature process for preparing linear polyesters frommacrocyclic polyester oligomers.

SUMMARY

One embodiment of this invention is a process for preparing a linearthermoplastic polyester comprising contacting at least one macrocyclicpolyester oligomer with at least one catalyst containing a lanthaniderare earth element or yttrium.

Another embodiment of this invention is a process for preparing a linearthermoplastic polyester comprising contacting at least one macrocyclicpolyester oligomer with at least one catalyst described by the formula:

wherein

M is a lanthanide rare earth element or yttrium;

R is H, alkyl, or aralkyl;

R′ is aliphatic hydrocarbyl or substituted hydrocarbyl;

N is 2 or 3; and

m is 1 or 0.

In a further embodiment of this invention, articles are produced using amacrocyclic polyester oligomer material (with or without fillers) bypolymerizing it in the process of forming the article, using processesincluding without limitation injection and rotational molding, resinfilm infusion, resin transfer molding, filament winding, powder coatingto create a prepreg or film, hot melt prepreg preparation, compressionmolding, roll wrapping, and pultrusion; and all of these optionally withreinforcement.

DETAILED DESCRIPTION

In the context of this disclosure, a number of terms shall be utilized.

As used herein, the term “hydrocarbyl” denotes a univalent radicalcontaining only carbon and hydrogen.

As used herein, the term “substituted hydrocarbyl” denotes a hydrocarbylgroup which contains one or more (types of) substituents that does notinterfere with the operation of the polymerization catalyst system.

As used herein, the term “alkyl” denotes a univalent group derived froman alkane by removing a hydrogen atom from any carbon atom:—C_(n)H₂₊₁ where n≧1.

As used herein, the term “aryl” denotes a univalent group whose freevalence is to a carbon atom of an aromatic ring. The aryl moiety maycontain one or more aromatic ring and may be substituted by inertgroups, i.e., groups whose presence does not interfere with theoperation of the polymerization catalyst system.

As used herein, the term “aralkyl” denotes an alkyl group, which bearsan aryl group. One such example is the benzyl group, i.e., the C₆H₅CH₂—radical.

As used herein, a “macrocyclic” molecule means a cyclic molecule havingat least one ring within its molecular structure that contains 8 or moreatoms covalently connected to form the ring.

As used herein, an “oligomer” means a molecule that contains 2 or moreidentifiable structural repeat units of the same or different formula.

As used herein, a “macrocyclic polyester oligomer” means a macrocyclicoligomer containing 2 or more identifiable ester functional repeat unitsof the same or different formula. A macrocyclic polyester oligomertypically refers to multiple molecules of one specific formula havingvarying ring sizes. However, a macrocyclic polyester oligomer may alsoinclude multiple molecules of different formulae having varying numbersof the same or different structural repeat units. A macrocyclicpolyester oligomer may be a co-oligoester or multi-oligoester, i.e., apolyester oligomer having two or more different structural repeat unitshaving an ester functionality within one cyclic molecule.

As used herein, “an alkylene group” means —C_(n)H_(2n)— where n≧1.

As used herein, “a cycloalkylene group” means a cyclic alkylene group,—C_(n)H_(2n-x)—, where x represents the number of H's replaced bycyclization(s).

As used herein, “a mono- or polyoxyalkylene group” means

[—(CH₂)_(y)—O—]_(n)—(CH₂)_(y)—, wherein y is an integer greater than 1and n is an integer greater than 0.

As used herein, “an alicyclic group” means a non-aromatic hydrocarbongroup containing a cyclic structure therein.

As used herein, “a divalent aromatic group” means an aromatic group withlinks to other parts of the macrocyclic molecule. For example, adivalent aromatic group may include a meta- or para-linked monocyclicaromatic group

As used herein, the term “lanthanide rare earth element” denotes amember of the group of elements whose atomic number is from 57 up to andincluding 71, specifically: lanthanum, cerium, praseodymium, neodymium,promethium, samarium, europium, gadolinium, terbium, dysprosium,holmium, erbium, thullium, ytterbium, and lutetium.

As used herein, “a polyester polymer composite” means a polyesterpolymer that is associated with another substrate such as a fibrous orparticulate material. Illustrative examples of particulate material arechopped fibers, glass microspheres, and crushed stone. Certain fillersand additives thus can be used to prepare polyester polymer composites.A fibrous material means more continuous substrate, e.g., fiberglass,ceramic fibers, carbon fibers or organic polymers such as aramid fibers.

As used herein, “wet-out” means a process to cause a physical state ofgood and sustained contact between a liquid substrate and a solidsubstrate such that no substantial amount of air or other gas is trappedbetween the liquid substrate and the solid substrate.

As used herein, “fiber” means any material with slender, elongatedstructure such as polymer or natural fibers. The material can befiberglass, ceramic fibers, carbon fibers or organic polymers such asaramid fibers.

As used herein, a fiber “tow” or “strand” is a group of fibers together,or a bundle of fibers, which are usually wound onto spools and may ormay not be twisted.

As used herein, a “fiber preform” is an assembly of fiber tows and/orfabric held together in a desired shape.

As used herein, a “prepreg” is a fiber material such as carbon fiber,glass fiber, or other fiber, that has been impregnated with a resinmaterial in sufficient volume as to provide the matrix of the composite,and such that the ratio of fiber to resin is closely controlled. Thefiber configuration can be in tow form, woven or knitted into a fabric,or in a unidirectional tape.

Where a range of numerical values is recited herein, unless otherwisestated, the range is intended to include the endpoints thereof, and allintegers and fractions within the range. It is not intended that thescope of the invention be limited to the specific values recited whendefining a range.

It has been found that compounds containing a lanthanide rare earthelement or yttrium effectively catalyze the ring opening polymerizationof macrocyclic polyester oligomers. Such catalysts are stable at hightemperatures during the polymerization and result in high monomerconversion, high molecular weight, and a mechanically sound material.The polymerization is rapid, with near-quantitative conversion typicallywithin five minutes.

Macrocyclic polyester oligomers that may be employed in this inventioninclude, but are not limited to, macrocyclic poly(alkylenedicarboxylate) oligomers having a structural repeat unit of the formula:

wherein A is an alkylene group containing at least two carbon atoms, acycloalkylene, or a mono- or polyoxyalkylene group; and B is a divalentaromatic or alicyclic group.

Preferred macrocyclic polyester oligomers are macrocyclic polyesteroligomers of 1,4-butylene terephthalate (CBT); 1,3-propyleneterephthalate (CPT); 1,4-cyclohexylenedimethylene terephthalate (CCT);ethylene terephthalate (CET); 1,2-ethylene 2,6-naphthalenedicarboxylate(CEN); the cyclic ester dimer of terephthalic acid and diethylene glycol(CPEOT); and macrocyclic co-oligoesters comprising two or more of theabove structural repeat units.

Synthesis of the macrocyclic polyester oligomers may be achieved bycontacting at least one diol of the formula HO-A-OH with at least onediacid chloride of the formula:

where A and B are as defined above. The reaction typically is conductedin the presence of at least one amine that has substantially no sterichindrance around the basic nitrogen atom. See, e.g., U.S. Pat. No.5,039,783 to Brunelle et al.

Another method for preparing macrocyclic polyester oligomers is byreacting at least one diester of B with at least one diol of the formulaHO-A-OH, using a N-heterocyclic carbene catalyst as described inco-pending U.S. Provisional Application No. 60/xxxxxx, where A and B areas defined above. This leads to a mixture containing appreciable amountsof macrocyclic polyester oligomer.

Macrocyclic polyester oligomers also can be prepared via thecondensation of a diacid chloride with at least one bis(hydroxyalkyl)ester such as bis(4-hydroxybutyl)terephthalate in the presence of ahighly unhindered amine or a mixture thereof with at least one othertertiary amine such as triethylamine. The condensation reaction isconducted in a substantially inert organic solvent such as methylenechloride, chlorobenzene, or a mixture thereof. See, e.g., U.S. Pat. No.5,231,161 to Brunelle et al.

A recent paper, A. Lavalette, et al., Biomacromolecules, vol. 3, p.225-228 (2002), describes a process whereby an enzymatically catalyzedreaction of dimethyl terephthalate and di(ethylene glycol) orbis(2-hydroxyethyl)thioether leads to essentially complete formation ofthe dimeric cyclic ester, while use of 1,5-pentanediol leads to arelatively high yield of the dimeric cyclic ester, along with somelinear polyester.

Macrocyclic polyester oligomers also can be prepared from linearpolyester oligomers in a solvent using an enzyme catalyst, such as alipase, protease, or esterase (PCT Patent Application WO 2003/093491 toBrugel and Di Cosimo).

Another method for preparing macrocyclic polyester oligomers ormacrocyclic co-oligoesters is the depolymerization of linear polyesterpolymers in the presence of an organotin or titanate compound. In thismethod, linear polyesters are converted to macrocyclic polyesteroligomers by heating a mixture of linear polyesters, an organic solvent,and a transesterification catalyst such as a tin or titanium compound.The solvents used, such as o-xylene and o-dichlorobenzene, usually aresubstantially free of oxygen and water. See, e.g., U.S. Pat. No.5,407,984 to Brunelle et al. and U.S. Pat. No. 5,668,186 to Brunelle etal.

Macrocyclic polyester oligomers can be obtained through extraction fromlinear polyester. For example, Brugel in PCT Patent Application WO2002/068496 teaches a continuous reactive extraction process, using afluid such as an n-alkane or a perfluorocompound to extract macrocyclicester oligomers from molten linear polyester. Macrocyclic polyesteroligomers can also be obtained through extraction from low-molecularweight linear polyester. For example, CPT can be isolated from linearPPT oligomers by glycol extraction. The linear PPT oligomers areconveniently obtained during the manufacture of PPT, as they collect onbag filters during the finishing step in the manufacturing process.

It is also within the scope of the invention to employ macrocyclicco-oligoesters to produce copolyesters. Therefore, unless otherwisestated, an embodiment of a composition, article, or process that refersto macrocyclic polyester oligomers also includes embodiments utilizingmacrocyclic co-oligoesters.

Catalysts employed in the present invention are chemical compounds thatcontain at least one member of the group consisting of lanthanide rareearth elements and yttrium. A few illustrative examples are lanthanumtris(2,2,6,6-tetramethylheptanedionato), cerium tris-cyclopentadienyl,samarium trifluoromethane sulfonate, ceriumtetrakis-(2,2,6,6-tetramethylheptanedionato), and yttriumbis-acetylacetonate isopropoxide.

Preferred are compounds of the formula

wherein

M is a lanthanide rare earth element or yttrium;

R is H, alkyl, or aralkyl;

R′ is aliphatic hydrocarbyl or substituted hydrocarbyl;

N is 2 or 3; and

m is 1 or 0.

The polymerization reaction is carried out at an elevated temperature,typically in the range of about 180 to about 280° C., by heating to thetemperature at which the polymerization occurs. Typically, themacrocyclic polyester oligomer is heated to above its melting point soit becomes less viscous and can be manipulated easier in processing.Stirring may be employed under an inert atmosphere. The polymerizationreaction may be carried out with or without a solvent. A solvent may beused to dissolve one or more of the reactants and/or to mix thereactants. A solvent may also be used as a medium in which the reactionis carried out. Illustrative solvents that may be used includehigh-boiling compounds such as o-dichlorobenzene and meta-terphenyl. Ina preferred embodiment, no solvent is used in the polymerizationreaction.

The amount of catalyst used is typically in the range of 1000 to 10,000ppm by weight of the macrocyclic polyester oligomer used.

In one aspect of the invention, articles are produced using amacrocyclic polyester oligomer material (with or without fillers) bypolymerizing it in the process of forming the article, using processesincluding without limitation injection and rotational molding, resinfilm infusion, resin transfer molding, filament winding, powder coatingto create a prepreg or film, hot melt prepreg preparation, compressionmolding, roll wrapping, and pultrusion; and all of these optionally withreinforcement. The only proviso is that conditions allow for thepolymerization of the macrocyclic polyester oligomer to form highmolecular weight polyester; that is, the macrocyclic polyester oligomershould be heated at least to its melting point. Generally, most of suchprocesses require that the resin to be processed have a low meltviscosity; therefore, macrocyclic polyester oligomers, which have lowmelt viscosity, viscosity are particularly suitable for such processing(see, e.g., U.S. Pat. No. 6,369,157).

For example, a molding process for manufacturing articles from amacrocyclic polyester oligomer includes placing in a mold at least onemacrocyclic polyester oligomer and at least one catalyst described asset forth above, and heating the contents of the mold to a temperaturehigh enough for polymerization of the oligomer to take place. This isabove the melting point of the oligomer, typically in the range of about180 to about 280° C. Molten oligomer and catalyst can be injected intothe mold at much lower pressure than the 5,000 to 20,000 psi typical ofinjection molding processes because of the low viscosity of the moltenoligomer.

In compression molding, the oligomer(s) and catalyst(s) are placedbetween a top die and a lower die within a press. The oligomer(s) andcatalyst(s) are typically loaded onto a fibrous base material. The diesof the mold are pressed together with enough pressure to evenly fill themold, and the mold contents are heated to a high enough temperature forpolymerization to take place. Compression molding is used for makingplastic composite parts that are thin and generally flat with mildfeatures and contours such as truck and auto body panels, bumper beams,various trays and machine housings.

In rotational molding, the molding process additionally comprisesrotating the mold about two axes simultaneously, so that the contentsroll over the intended areas of the inside of the mold, beginning therotation before the contents are heated, and continuing to rotate themold until the content polymerizes and solidifies. Rotational molding isa process for making hollow thermoplastic articles, such as a widevariety of fluid storage tanks, tractor fenders and large children'stoys.

In resin film infusion, a layer or film of the macrocyclic polyesteroligomer(s) containing the catalyst(s) is placed in the mold adjacent toa dry layer of fibrous material, and, when the contents of the mold areheated, the oligomer(s) and catalyst(s) are forced to infuse into thedry layer of fibrous material. Resin film infusion is a process formaking plastic composite articles that are predominantly flat on oneface and may have detailed features. An illustrative example of sucharticles is aircraft wing skins, which are typically constructed of acomposite made with carbon fiber and epoxy resin.

The compositions and methods of the invention may be used to manufacturearticles of various sizes and shapes from various macrocyclic polyesteroligomers. Exemplary articles that may be manufactured by the inventioninclude without limitation automotive body panels and chassiscomponents, bumper beams, aircraft wing skins, windmill blades, fluidstorage tanks, tractor fenders, tennis rackets, golf shafts, windsurfingmasts, toys, rods, tubes, bars stock, bicycle forks, and machinehousings.

In the manufacture of an article, one or more of various types offillers may be included. A particular filler often is included toachieve a desired purpose or property, and may be present in theresulting polyester polymer. For example, the purpose of the filler maybe to increase the strength of the polyester polymer product. Boronnitride is used as a filler in applications that require high levels ofheat conductivity and low levels of electrical conductivity. A filleralso may provide weight or bulk to achieve a particular density, be asubstitute for a more expensive material, and/or provide other desirableproperties as recognized by a skilled artisan. Illustrative examples offillers are, among others, fumed silica, titanium dioxide, calciumcarbonate, chopped fibers, fly ash, glass microspheres, micro-balloons,crushed stone, nanoclay, linear polymers, and monomers. A filler may beadded before, during or after the polymerization reaction between amacrocyclic polyester oligomer and a cyclic ester. The filler is addedgenerally between about 0.1% and 70% by weight of the totalpolymerizable composition (i.e., oligomer plus catalyst plus filler plusany other additives that may be present), depending on the filler andthe purpose for adding the filler. For example, the percentage ispreferably between 25% and 50% by weight in the case of calciumcarbonate, between 2% and 5% by weight in the case of nanoclays, andbetween 25% and 70% by weight in the case of glass microspheres. Fillerscan be used to prepare polyester polymer composites.

Furthermore, in the manufacture of an article, additional components(e.g., additives) may be added. Illustrative additives includecolorants, pigments, magnetic materials, antioxidants, UV stabilizers,plasticizers, flame retardants, lubricants, and mold releases.

EXAMPLES

The present invention is further defined in the following Examples. Itshould be understood that these Examples, while indicating preferredembodiments of the invention, are given by way of illustration only.From the above discussion and these Examples, one skilled in the art canascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various uses andconditions.

The meaning of abbreviations is as follows: “min” means minute(s), “sec”means second(s), “g” means gram(s), “mmol” means millimole(s), “M_(n)”means number average molecular weight, “M_(w)” means weight averagemolecular weight, “GPC” means gel permeation chromatography, “DMA” meansdynamic mechanical analysis, “DSC” means differential scanningcalorimetry, “T_(g)” means glass transition temperature, “T_(m)” meansmelting temperature, and “T_(c)” means crystallization temperature.

Experimental

Materials.

CPT was isolated from poly(1,3-propylene terephthalate) via a warmglycol extraction from linear oligomers that were isolated on bagfilters during the finishing step during the manufacture ofpoly(1,3-propylene terephthalate). CBT was isolated frompoly(1,4-butylene terephthalate) described in WO 2002068496. CPCT(cyclic poly(cyclohexanedimethanol terephthalate)) was prepared asdescribed in Wan, X.-H. Y., Yi; Tu, Hui-Lin; Huang, Lan; Tan, Samuel;Zhou, Qi-Feng; Turner, S. Richard, “Synthesis, characterization, andring opening polymerization of poly(1,4-cyclohexylenedimethyleneterephthalate) cyclic oligomers.” Journal of Polymer Science, Part A:Polymer Chemistry, 2000, Vol. 38, pp. 1828-1833.

CPEOT was prepared as follows: A 22-L jacketed resin kettle equippedwith overhead stirrer and Dean-Stark trap was charged with 9.246 L oftoluene, 265.3 grams (2.50 mole) of diethylene glycol, and 485.5 g (2.50mole) of dimethylterephthalate. The resulting mixture was heated to 80°C. with stirring until the dimethylterephthalate had dissolved, then 300g of immobilized Candida antartica lipase B (Novozyme 435) was added.The resulting mixture was maintained at 80° C. while being sparged withnitrogen at 8.5 L/minute, and toluene lost due to sparging was replacedperiodically. After 24 h, the nitrogen sparge was discontinued and thereaction mixture was discharged from the kettle at 80° C. Toluene wasdistilled from the product mixture at 70° C. and 50 mm vacuum, theresulting solids (1050 g) were divided into three equal portions, andeach portion extracted with 11 L of refluxing chloroform for 3 h. Thehot chloroform extract was filtered to remove the enzyme catalyst, andthe resulting filtrate concentrated to about 3.5 L, cooled to roomtemperature, filtered, and the recovered white solid air-dried toproduce a total of 490 g (83% yield, 99% purity) of3,6,9,16,19,22-hexaoxatricyclo[22.2.2.211,14]triaconta-11,13,24,26,27,29-hexaene-2,10,15,23-tetrone,also known as “cyclic poly(diethyleneglycol terephthalate)” or CPEOT.

Yttrium tris(2,2,6,6-tetramethylheptanedionato), lanthanumtris(2,2,6,6-tetramethylheptanedionato), yttrium bis-acetylacetonateisopropoxide, cerium tris-cyclopentadienyl, ceriumtetrakis-(2,2,6,6-tetramethylheptanedionato), samarium trifluoromethanesulfonate, lanthanum bis(2,2,6,6tetramethylheptanedionato)isopropoxide,dibutyltin oxide, were obtained from Strem Chemicals, Inc. (Newburyport,Mass.) and were used as received.

Polymer Characterization.

A size exclusion chromatography system comprised of a Model Alliance2690™ from Waters Corporation (Milford, Mass.), with a Waters 410™refractive index detector (DRI) and Viscotek Corporation (Houston, Tex.)Model T-60A™ dual detector module incorporating static right angle lightscattering and differential capillary viscometer detectors was used formolecular weight characterization. The mobile phase was1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) with 0.01 M sodiumtrifluoroacetate The dn/dc was measured for the polymers and it wasassumed that all of the sample was completely eluted during themeasurement.

EXAMPLE 1 Polymerization of cyclic poly(1,3-propylene terephthalate)with yttrium tris(2,2,6,6-tetramethylheptanedionato)

Cyclic poly(1,3-propylene terephthalate) (4.96 g, 12.13 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, yttriumtris(2,2,6,6-tetramethylheptanedionato) (0.127 g, 0.2mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec and then the scintillation vial was capped and the polymerizationwas allowed to proceed for 15 min. GPC Analysis: Yield=92%,M_(n)=27,700, M_(w)=47500, M_(w)/M_(n)=1.71.

EXAMPLE 2 Polymerization of cyclic poly(1,3-propylene terephthalate)with lanthanum tris(2,2,6,6-tetramethylheptanedionato)

Cyclic poly(1,3-propylene terephthalate) (5.04 g, 12.23 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, lanthanumtris(2,2,6,6-tetramethylheptanedionato) (0.138 g, 0.2 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. During the initial 30 sec, the polymerization mixture becamehighly viscous until the molten mixture of the polymer and monomer didnot flow. The scintillation vial was capped and the polymerization wasallowed to proceed for 15 min. GPC Analysis: Yield=90%, M_(n)=20,000,M_(w)=37200, M_(w)/M_(n)=1.86.

EXAMPLE 3 Polymerization of cyclic poly(1,3-propylene terephthalate)with yttrium bis-acetylacetonate isopropoxide

Cyclic poly(1,3-propylene terephthalate) (5.04 g, 12.23 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, yttriumbis-acetylacetonate isopropoxide ( 0.104 g, 0.2mmol) was added to themolten monomer. The catalyst and monomer were stirred vigorously for 10sec. During the initial 30 sec, the polymerization mixture became highlyviscous until the molten mixture of the polymer and monomer did notflow. The scintillation vial was capped and the polymerization wasallowed to proceed for 15 min. GPC Analysis: Yield=91%, M_(n)=21,300,M_(w)=37200, M_(w)/M_(n)=1.74

EXAMPLE 4 Polymerization of cyclic poly(1,3-propylene terephthalate)with cerium tris-cyclopentadienyl

Cyclic poly(1,3-propylene terephthalate) (5.04 g, 12.23 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, ceriumtris-cyclopentadienyl (0.067 g, 0.2mmol) was added to the moltenmonomer. The catalyst and monomer were stirred vigorously for 10 sec.The scintillation vial was capped and the polymerization was allowed toproceed for 15 min. GPC Analysis: Yield=66%, M_(n)=19600, M_(w)=42,100,M_(w)/M_(n)=2.15

EXAMPLE 5 Polymerization of cyclic poly(1,3-propylene terephthalate)with cerium tetrakis-(2,2,6,6-tetramethylheptanedionato)

Cyclic poly(1,3-propylene terephthalate) (4.99 g, 12.11 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, ceriumtetrakis-(2,2,6,6-tetramethylheptanedionato) (0.175 g, 0.2mmol) wasadded to the molten monomer. The catalyst and monomer were stirredvigorously for 10 sec. The polymerization melt became highly viscous andstopped flowing within 1 min. The scintillation vial was capped and thepolymerization was allowed to proceed for 30 min. GPC Analysis:Yield=91%, M_(n)=26,700, M_(w)=52,800, M_(w)/M_(n)=1.98.

EXAMPLE 6 Polymerization of cyclic poly(1.3-propylene terephthalate)with samarium trifluoromethane sulfonate

Cyclic poly(1,3-propylene terephthalate) (4.98 g, 12.08 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, samariumtrifluoromethane sulfonate (0.12 g, 0.2 mmol) was added to the moltenmonomer. The catalyst and monomer were stirred vigorously for 10 sec.The scintillation vial was capped and the polymerization was allowed toproceed for 20 min. GPC Analysis: Yield=39%, M_(n)=28,600, M_(w)=61,800,M_(w)/M_(n)=2.16.

EXAMPLE 7 Polymerization of cyclic poly(1,3-propylene terephthalate)with yttrium tris(2,2,6,6-tetramethylheptanedionato)

Cyclic poly(1,3-propylene terephthalate) (15 g, 36.4 mmol) was added toa dried scintillation vial and heated to 270° C. After the cyclicpoly(1,3-propylene terephthalate) was completely melted, yttriumtris(2,2,6,6-tetramethylheptanedionato) (0.127 g, 0.2 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec and then the scintillation vial was capped and the polymerizationwas allowed to proceed for 15 min. GPC Analysis: Yield=80%,M_(p)=75,700.

EXAMPLE 8 Polymerization of cyclic poly(1,4butylene terephthalate) withlanthanum tris(2,2,6,6-tetramethylheptanedionato)

Cyclic poly(1,4-butylene terephthalate) (5.04 g, 11.45 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,4-butylene terephthalate) was completely melted, lanthanumtris(2,2,6,6-tetramethylheptanedionato) (0.14g, 0.2 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. The molten monomer and polymer solution rapidly increased inviscosity, and within 30 sec the solution did not flow. Thescintillation vial was capped and the polymerization was allowed toproceed for 6 min. GPC Analysis: Yield=79%, M_(n)=76,300, M_(w)=152,000,M_(w)/M_(n)=1.99.

EXAMPLE 9 Polymerization of cyclic poly(1,4-butylene terephthalate) withyttrium bis(acetylacetonate)isopropoxide

Cyclic poly(1,4-butylene terephthalate) (5.08 g, 11.54 mmol) was addedto a dried scintillation vial and heated to 270° C. After the cyclicpoly(1,4-butylene terephthalate) was completely melted, yttriumbis(acetylacetonate) isopropoxide (0.14g, 0.2 mmol) was added to themolten monomer. The catalyst and monomer were stirred vigorously for 10sec. The molten monomer and polymer solution rapidly increased inviscosity, and within 30 sec the solution did not flow. Thescintillation vial was capped and the polymerization was allowed toproceed for 4 min. GPC Analysis: Yield=94%, M_(n)=17,900, M_(w)=34,100,M_(w)/M_(n)=1.91.

EXAMPLE 10 Copolymerization of cyclic poly(1,3-propylene terephthalate)and cyclic poly(diethyleneglycol terephthalate) with lanthanumtris(2,2,6,6-tetramethylheptanedionato)

A mixture of cyclic poly(1,3-propylene terephthalate) (0.501 g, 1.21mmol) and cyclic poly(dliethyleneglycol terephthalate) (0.503 g, 1.06mmol) was added to a dried scintillation vial and heated to 270° C.After the cyclic monomers were completely melted, lanthanumtris(2,2,6,6-tetramethylheptanedionato) (0.028g, 0.04 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. The scintillation vial was capped and the polymerization wasallowed to proceed for 10 min. GPC Analysis: Yield=94%, M_(n)=17,900,M_(w)=48,800, M_(w)/M_(n)=2.61.

EXAMPLE 11 Copolymerization of cyclic poly(1,3-propylene terephthalate)and cyclic poly(diethyleneglycol terephthalate) with lanthanumtris(2,2,6,6-tetramethylheptanedionato)

A mixture of cyclic poly(1,3-propylene terephthalate) (0.499 g, 1.21mmol) and cyclic poly(diethyleneglycol terephthalate) (0.502g, 1.06mmol) was added to a dried scintillation vial and heated to 210° C.After the cyclic monomers were completely melted, lanthanumtris(2,2,6,6-tetramethylheptanedionato) (0.028g, 0.04 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. The scintillation vial was capped and the polymerization wasallowed to proceed for 30 min. GPC Analysis: Yield=94%, M_(n)=47,000,M_(w)=100,100, M_(w)/M_(n)=2.13 DMA Analysis: T_(g)=44° C., T_(m)=140°C., Tensile Modulus=1231 MPa at 25° C.

EXAMPLE 12 Copolymerization of cyclic poly(1,3-propylene terephthalate)and cyclic poly(diethyleneglycol terephthalate) with lanthanumtris(2,2,6,6-tetramethylheptanedionato)

A mixture of cyclic poly(1,3-propylene terephthalate) (0.5 g, 1.20 mmol)and cyclic poly(diethyleneglycol terephthalate) (0.502g, 1.06 mmol) wasadded to a dried scintillation vial and heated to 210° C. After thecyclic monomers were completely melted, lanthanumtris(2,2,6,6-tetramethylheptanedionato) (0.138 g, 0.2 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. The scintillation vial was capped and the polymerization wasallowed to proceed for 30 min. DMA Analysis: T_(g)=56° C., TensileModulus=1454 MPa at 25° C. DSC Analysis: T_(g)=41° C., T_(m)=203° C.,T_(c)=152° C. Percent Conversion=99%.

EXAMPLE 13 Polymerization of poly(diethylene glycol terephthalate) withlanthanum tris(2,2,6,6tetramethylheptanedionato)

Cyclic poly(diethyleneglycol terephthalate) (5.04 g, 10.67 mmol) wasadded to a dried scintillation vial and heated to 210° C. After thecyclic was completely melted, lanthanumtris(2,2,6,6tetramethylheptanedionato) (0.14 g, 0.2 mmol) was added tothe molten monomer. The catalyst and monomer were stirred vigorously for10 sec. The molten monomer and polymer solution rapidly increased inviscosity, and within 30 sec the solution did not flow. Thescintillation vial was capped and the polymerization was allowed toproceed for 12 min. GPC Analysis Yield=92%, M_(p)=54,500.

EXAMPLE 14 Polymerization of Cyclic poly(diethyleneglycol terephthalate)with lanthanum bis(2,2,6,6tetramethylheptanedionato)isopropoxide

Cyclic poly(diethyleneglycol terephthalate) (4.96 g, 10.51 mmol) wasadded to a dried scintillation vial and heated to 210° C. After thecyclic was completely melted, lanthanumbis(2,2,6,6tetramethylheptanedionato)isopropoxide (0.10 g, 0.2 mmol) wasadded to the molten monomer. The catalyst and monomer were stirredvigorously for 10 sec. The molten monomer and polymer solution rapidlyincreased in viscosity, and within 30 sec the solution did not flow. Thescintillation vial was capped and the polymerization was allowed toproceed for 5 min. GPC Analysis: Yield=90%, M_(p)=40,300.

EXAMPLE 15 Polymerization of Cyclic poly(cyclohexanedimethanolterephthalate) with lanthanum tris(2,2,6,6tetramethylheptanedionato)

Cyclic poly(cyclohexanedimethanol terephthalate) (0.5 g) was melted at280° C. and lanthanum tris (2,2,6,6tetramethylheptanedionato) (0.0138 g)was added with rapid stirring. The reaction rapidly became viscous andwithin 30 min would not flow.

COMPARATIVE EXAMPLE 1 Polymerization of Cyclic poly(1,3-propyleneterephthalate)with dibutyl tin oxide

Cyclic poly(1,3-propylene terephthalate) (10.00 g, 48.55 mmol) was addedto a dried round-bottomed flask and heated to 280° C. until molten.Dibutyl tin oxide (0.14565 mmol, 0.036 g) was added and thepolymerization was allowed to proceed for 30 min. The polymer remained alow viscosity material. GPC Analysis: M_(n)=390, M_(w)=7930.

1. A process for preparing a thermoplastic polyester comprisingcontacting at least one macrocyclic polyester oligomer with at least onecatalyst containing a lanthanide rare earth element or yttrium.
 2. Theprocess of claim 1 wherein the catalyst is described generally by theformula:

wherein M is a lanthanide rare earth element or yttrium; R is H, alkyl,or aralkyl; R′ is aliphatic hydrocarbyl or substituted hydrocarbyl; N is2 or 3; and m is 1 or
 0. 3. The process of claim 2 wherein R is anaralkyl group and is attached by an alkyl linkage.
 4. The process ofclaim 1 or 2 which is carried out at a temperature of about 180 to about280° C.
 5. The process of claim 1 or 2 wherein the macrocyclic polyesteroligomer is contacted with the catalyst in the presence of a filler. 6.The process of claim 5 wherein the weight of the filler is 0.1 to 70% ofthe total weight of oligomer plus catalyst plus filler plus any otheradditives present.
 7. The process of claim 5 wherein the filler is atleast one member of the group consisting of boron nitride, fumed silica,titanium dioxide, calcium carbonate, chopped fibers, fly ash, glassmicrospheres, micro-balloons, crushed stone, nanoclay, linear polymers,and monomers.
 8. A process for manufacturing an article from macrocyclicpolyester oligomer, comprising the steps: (a) providing to a mold atleast one macrocyclic polyester oligomer and at least one catalystcontaining a lanthanide rare earth element or yttrium, and (b) heatingthe contents of the mold to a temperature at which polymerization of theoligomer occurs.
 9. The process of claim 8 wherein the macrocyclicpolyester oligomer is molten and is injected into the mold.
 10. Theprocess of claim 8 further comprising a step of rotating the mold abouttwo axes simultaneously so that the contents roll over the intendedareas of the inside of the mold, beginning the rotation before thecontents are heated, and continuing to rotate the mold until the contentpolymerizes and solidifies.
 11. The process of claim 8 wherein a layeror film of the macrocyclic polyester oligomer(s) comprising thecatalyst(s) is placed in the mold adjacent to a dry layer of fibrousmaterial, and, when the contents of the mold are heated, the oligomer(s)and catalyst(s) are forced to infuse into the dry layer of fibrousmaterial.
 12. The process of claim 8 wherein the mold contains a fibrousperform, and the macrocyclic polyester oligomer(s) and catalyst(s) areforced into the preform.
 13. The process of claim 8 wherein theoligomer(s) and catalyst(s) are placed between a top die and a lower diewithin a press, and the dies of the mold are pressed together to evenlyfill the mold with the oligomer(s) and catalyst(s).
 14. A process forforming a prepreg from a macrocyclic polyester oligomer and apolymerization catalyst comprising the steps: (a-1) dissolving at leastone macrocyclic polyester oligomer and at least one catalyst containinga lanthanide rare earth element or yttrium in a solvent to form asolution thereof; (a-2) contacting the solution with a fibrous basematerial: and (a-3) removing the solvent; or (b-1) providing a releasebase material; (b-2) coating thereon a layer of at least one macrocyclicpolyester oligomer and at least one catalyst containing a lanthaniderare earth element or yttrium; and (b-3) pressing the release basematerial against a fibrous base material under heat; or (c-1) providingat least one macrocyclic polyester oligomer, and at least one catalystcontaining a lanthanide rare earth element or yttrium, as a powder;(c-2) impregnating a coating of the powder of step c-1 into a fibrousbase material; (c-3) softening the oligomer; and (c-4) applying heat andpressure to cause the oligomer to flow and polymerizein the fibrous basematerial.
 15. The process of claim 14 wherein the fibrous base materialis a fabric, fiber tow, or unidirectional prepreg tape.
 16. A pultrusionprocess for making a fiber reinforced article, comprising the steps: (a)providing at least one macrocyclic polyester oligomer and at least onecatalyst containing a lanthanide rare earth element or yttrium; (b)pulling a fibrous strand into an elongated die; (c) causing themacrocyclic polyester oligomer(s) and the catalyst(s) to contact withand around the fibrous strand in the die; (d) heating to causepolymerization of the macrocyclic polyester oligomer forming highmolecular weight polyester resin matrix around the fibrous strand; and(e) pulling the polyester matrix into an exit portion of the die havinga desired cross section thereby forming an article.
 17. The process ofclaim 18 wherein the macrocyclic polyester oligomer is continuouslymelted outside the die and pumped into the die in liquid form.
 18. Afilament winding process for manufacturing hollow plastic compositearticles from macrocyclic polyester oligomers, comprising the steps: (a)providing at least one macrocyclic polyester oligomer and at least onecatalyst containing a lanthanide rare earth element or yttrium; (b)contacting the macrocyclic polyester oligomer(s) and the polymerizationcatalyst(s) with a fibrous strand; (c) winding the fibrous strand onto amandrel; and (d) heating the macrocyclic polyester oligomer to atemperature at which polymerization thereof occurs.
 19. A roll wrappingprocess for manufacturing tubular articles from macrocyclic polyesteroligomers, comprising the steps: (a) forming a prepreg by impregnating asheet or tape of reinforcing fibers with at least one macrocyclicpolyester oligomer and at least one catalyst containing a lanthaniderare earth element or yttrium; (b) rolling the prepreg onto a mandrel;and (c) heating the macrocyclic polyester oligomer to a temperature atwhich polymerization thereof occurs.
 20. The process of any of claims 8,14, 16, 18 or 19 wherein the lanthanide-containing catalyst is describedby the formula

wherein M is a lanthanide rare earth element or yttrium; R is H, alkyl,or aralkyl; R′ is aliphatic hydrocarbyl or substituted hydrocarbyl; N is2 or 3; and m is 1 or
 0. 21. The process of any of claims 8, 14, 16, 18or 19 wherein at least one filler is present in contact with themacrocyclic polyester oligomer.
 22. The process of claim 21 wherein theweight of the filler is 0.1 to 70% of the total weight of oligomer pluscatalyst plus filler plus any other additives present.
 23. The processof claim 21 wherein the filler is at least one member of the groupconsisting of boron nitride, fumed silica, titanium dioxide, calciumcarbonate, chopped fibers, fly ash, glass microspheres, micro-balloons,crushed stone, nanoclay, linear polymers, and monomers.